Heat can have detrimental effects on any solid state electronic device if not properly monitored and controlled. Unfortunately, heat is a natural occurring by-product of any working solid state electronic device. This is due to the intimate relationship between heat and power. As a solid state device draws power and completes its task to which it is designed to accomplish, heat is generated. In some devices, the heat generated, and therefore subjected upon the device, is low in comparison to the total "heat stress" that the device can stand. In other devices however, heat is the enemy.
Nowhere is heat more detrimental in a solid state electronic device than in semiconductors. In particular, the heat generated by a central processing unit (CPU) of a computer, if not properly dissipated, is certain to destroy the CPU. As technical advancements increase the speed of computer CPUs, so causes the need for more power to run the faster CPUs, and hence more heat is generated. Improvements upon heat dissipators for computer CPUs have been developed. But as will be shown, these improvements are falling well short of the need for a superior heat dissipator for fast-speed, high-heat generating computer CPUs.
The heat generated by an older style CPU, such as a 286 or 386 based processor, did not require the use of a heat dissipator. The heat generated by these processors was merely allowed to dissipate through convection cooling--heat transfer by the natural upwardly flow of hot air from the processor. But as CPUs advanced, such as the 486, Pentium and other faster processors, a need for additional cooling was required. Typically, these faster CPUs were equipped with a heat sink mounted on top of the CPU and a fan mounted on top of the heat sink for blowing air through the heat sink fins towards the top of the CPU. Such a cooling device can be seen in U.S. Pat. No. 5,603,374 to We. Unfortunately, this device has many deficiencies. In particular, the device relies on a single heat sink and fan assembly. This type of configuration may be adequate for an older style processor, such as a 486-based processor, but is surely not adequate for dissipating the heat generated by Pentium-based and other faster style processors. Further, the single fan assembly does not provide any redundancy to the heat dissipation system. If the single fan fails, the cooling system will not provide the necessary cooling ability required. The result is thermal run-away of the CPU and its subsequent failure in operation. Still further, the "stacking" of a heat sink and fan on top of a processor tends to cause spacing problems when used with today's processors. This can be attributed to the large heat sinks required for today's processors. The size of the heat sink tends to be proportional to the amount of heat generated by a fast-speed processor. In other words, very fast processors require very large heat sinks. Further, many of today's processors are mounted on a daughter board which in turn plugs into the motherboard at a ninety degree angle (i.e., Slot 1 or Slot A configuration), distinguishing those mounted directly to the motherboard in a parallel relationship (i.e., Socket 7 configuration)--also known as a "socketed" processor. The daughter board mounts (Slot 1 or Slot A) require the conservative use of space, especially when a pair of mounts or slots are provided for dual processing capabilities.
In an effort to limit the size of the heat sink, various improvements were made in order to provide a superior heat sink having a low profile. Such can be seen in U.S. Pat. No. 5,794,685 to Dean. The device shown therein employs a heat sink for mounting directly to the CPU having a generally circular shape. A single fan mounts to the top of the heat sink. This low profile device attempts to provide greater heat dissipation through matching the form of the heat sink to the blade configuration of the fan. Although this cooling system may provide greater cooling effects than that seen in the We device, it still falls short of providing adequate cooling for the faster processors used in today's computers. Further, this system would not work well with a CPU mounted on a daughter board, due to the fact that the circular-shaped heat sink does not provide an adequate means for attaching the heat sink and fan to the CPU. All daughter board mounted cooling assemblies require some form of mounting means which will retain the cooling system to the CPU when the daughter board is plugged into the motherboard at the ninety degree angle. Still further, this system does not provide adequate redundancy, in that only one fan is employed.
Attempts to limit the profile of the cooling system to provide adequate cooling to today's faster CPUs can be seen in U.S. Pat. No. 5,309,983 to Bailey, U.S. Pat. No. 5,615,084 to Anderson et al. and U.S. Pat. No. 5,873,406 to Hong. Each of these cooling systems employs some type of single heat sink and single fan assembly, wherein the fan rests in an alcove formed in the heat sink. Each system addresses the problem of limited spacing inside of a computer, but does not adequately address other problems inherent in the prior art. For instance, none of these devices contemplate the use of more than one fan. Accordingly, redundancy is not provided and the failing of the fan results in inadequate cooling capabilities (thermal run-away of the processor). Further, although spacing is addressed in these devices, the need for additional cooling elements for faster-speed CPUs is not contemplated. Accordingly, these devices may not adequately cool current and future processors.
To address the high heat problem of the faster speed processors, such as Pentium-based processors, certain improvements have been made for attempting to adequately cool these devices. U.S. Pat. No. 5,353,863 to You teaches a Pentium CPU cooling system including a heat sink mounted on top of the CPU and a fan mounted to the side of the heat sink. The invention herein attempts to utilize the fan to blow the heat generated by the CPU, and conducted through the heat sink, out of the computer case. Unfortunately, this device is very "product specific." Nowhere is it taught that the invention can be employed on a daughter board mounted CPU. In fact, this invention requires that the CPU be mounted on the motherboard in a location proximal to the computer housing vents, so that the hot air can be expelled out of the case through the vents. Further, no redundancy is suggested. Accordingly, upon failure of the single fan, the entire cooling system fails.
Other attempts to cool the faster processors can be seen in U.S. Pat. No. 5,771,153 to Sheng and U.S. Pat. No. 5,835,347 to CCU. Each of these inventions teach a system for cooling fast speed processors which are provided to consumers in plastic cases (i.e., Pentium-II or Pentium-III based processors). Unfortunately, these devices are very product specific. Each teach a cooling system which can be attached to the plastic case of the processor. Both require special clip mechanisms for attaching to the plastic case. Neither prior art reference suggest any form of redundancy and both rely on the single fan, single heat sink assembly.
Other various attempts at improved cooling systems have been attempted. U.S. Pat. No. 5,457,342 to Herbst II teaches a traditional prior art "stacked" cooling system with an additional cooling element--namely, a Peltier Effect cooling module. Peltier Effect cooling modules are electrical "heat pumps" which conduct heat from one side of the module to another through a conductor layer. Accordingly, when working properly, there is one hot and one cold side on any Peltier Effect module. In the prior art, Peltier Effect modules are inserted between the CPU and the heat sink. When working properly, the Peltier Effect module provides additional cooling to the CPU. But, if the Peltier Effect module fails, or if exposed to insufficient airflow due to fan failure, the module acts as an insulator between the CPU and heat sink thereby redirecting the heat back into the processor causing thermal run-away of the processor. Further, with the Peltier Effect module working properly, in scenarios when the processor is not generating a lot of heat, Peltier Effect modules which are mounted directly on the CPU are known to cool the processor below a safe operating range thereby depositing condensation on the processor and potentially damaging the processor.
U.S. Pat. No. 5,706,169 to Yeh discloses another cooling system for CPUs which provides for a single heat sink having two sections. Each section has a plurality of fins defining a plurality of first cooling ducts disposed in parallel relation. The two sections are spaced from one another by a single second cooling duct positioned perpendicular to the plurality of first cooling ducts. A fan is mounted on top of the heat sink. This device provides a cooling system having many of the inherent deficiencies as other prior art systems. It does not provide for redundant fans nor addresses many of the spacing problems seen with daughter board mounted processors.
An attempt at providing additional heat dissipation capabilities for a CPU resulted in the development of a product produced by ComputerNerd. The product utilizes a pair of heat sinks for surrounding a processor mounted on a daughter board. Fans are provided on the heat sink which is placed proximal to the die of the processor (front-side). A second heat sink is merely placed proximal to the back-side of daughter board, where the solder connections of the electrical components are located. Since 90% of all heat generated by a CPU emanates from the die area (front-side) of the processor, the second back-side heat sink provides essentially no additional heat dissipation for the processor, since the back-side heat sink fails to communicate in any manner with the front-side heat sink.
An improved cooling system is needed for computer CPUs and other solid state devices that generate substantial heat. The improved system should address all of the deficiencies seen in the prior art. In particular, an improved system should be provided which adequately dissipates heat from the high heat generating processors used in today's computers. Redundant fan assemblies should be provided to avoid thermal run-away of a processor due to the failure of the single fan. Additional heat sinks, thermally coupled, should also be provided which can assist in the conduction of the heat away from the processor, especially the heat generated on the front-side of a Slot 1 mounted processor. Adequate spacing should be provided for those processors mounted in Slot 1 or Slot A configurations. Such a system should also be non-product specific, working universally with all types of processors. If Peltier Effect modules are to be employed with the improved cooling system, the potential failure of the Peltier Effect module should be addressed for avoiding thermal run-away of the processor. In addition, the possible cooling of the processor to a point where condensation may form on the processor should also be addressed when considering the use of Peltier Effect modules.